1. Field of the Invention
This invention relates to automated vision systems for manufacturing and more particularly to a vision system for determining article positions during a manufacturing process.
2. Description of Related Information
Recently there has been increased interest in machine vision devices for industrial applications. This increased interest is attributed to the increased research in computer technology. Usually, the first step in vision analysis by a machine vision device is the conversion of analog pixel (picture element) data into digital data for processing by a computer. Historically, several different types of devices have been used. Most commonly used in early applications were the vidicon video tube cameras that produced analog video signals. More recently solid state cameras or cameras using charge-coupled devices (CCD) have been used. The use of the vidicon cameras and the solid state cameras is discussed in Chapter 2 of Machine Vision for Robotics and Automated Inspection, Vol. I--Fundamentals, by Richard K. Miller, published by Technical Insights, Inc. which is herein incorporated by reference. Chapter 4 entitled "Model Machine Vision Systems" and Chapter 9 entitled "General Methods to Enable Robots with Vision to Acquire, Orient and Transport Work Pieces" of this publication disclose different techniques used in the prior art to detect and determine the position of different objects.
A common technique used by these prior art vision systems is to take an N by M array representing the pixel elements of a view of the object and produce data representing this N by M array for analysis by a computer. As should be appreciated by those skilled in the art, such an analysis usually requires extensive computer resources and time to complete the analysis. Therefore, the use of vision systems in real time computer operations for support of manufacturing processing has been limited.
One early attempt to solve this problem is disclosed in U.S. Pat. No. 4,105,925 entitled "Optical Object Locator" which discloses a device for determining the position and orientation of an object on a conveyor by the use of two planes of light that intersect in a single transverse line on a conveyor surface. A linear diode array that is aligned along the single line of light on the conveyor detects light from that line by electronic sampling of the lumination of this linear array. Object boundaries are determined and object shape and orientation may thus be determined. Another patent entitled "Light Collection Apparatus" disclosed in U.S. Pat. No. 3,987,301 discloses an apparatus for detecting the presence of extraneous matter and/or cracks in translucent containers. The light collection apparatus incorporates an array of fiber optics elements arranged to perform an accurate and controllable method of light collection.
A further attempt at solving this problem is disclosed in "Device for Detecting the Position of Web Side Edge" in U.S. Pat. No. 4,146,797 which includes a single light emitting source, a lens to form a beam of light in the vicinity of a reference point and an optical fiber to transmit the light to a photoelectric converter. The output of the photoelectric converter is used to determine when the edge of the web has been detected.
The present invention has been embodied in an apparatus to provide vision information for a manufacturing environment. An object of the present invention is to provide a non-complex vision system that indicates the location and positioning of an article used in manufacture.
A further object of the present invention is to provide a vision apparatus that provides a digital output without having to perform analog to digital data conversions.
A further object of the present invention is to provide a vision apparatus that allows variations in optical resolution.